Catapult-makers were once ye olde celebrities

London - Catapult designers were the celebrity scientists of the ancient world, according to a British expert.

Until the discovery of gunpowder, the catapult was the most powerful weapon in existence, said historian Serafina Cuomo. The machines, capable of hurling large projectiles long distances, were in high demand during the time of the ancient Greeks and Romans - and so were their makers.

But the construction of catapults was no easy task, requiring great mathematical and engineering skill.

It became a science in itself, known as "belopoietics" from the Greek "poietike" meaning "making of" and "belos" meaning "projectile" or "projectile throwing device".

Cuomo, from the Centre for the History of Science at Imperial College London, said: "Belopoietics attracted the interest and financial support of governments. It combined geometry, physics, and technology. Ancient engineers saw their knowledge as cumulative and progressive and believed that they were making an important contribution to the welfare of cities and the power of kings and emperors."

The first catapults dated back as far as the Ninth Century BC when they were depicted in a relief from Nimrud, in present day Iraq. In the Forth Century BC they spread rapidly around the Mediterranean, said Cuomo, writing in the journal Science.

The earliest Greek catapult was the "belly bow" - a large bow mounted on a case, one end of which rested on the belly of the person using it. Later the weapon was enlarged and a winch pull-back system added.

The next step was to introduce "springs" - tight bundles of sinews or ropes that were tightly twisted to store enormous power. Eventually trial-and-error gave way to the principle that all parts of a catapult were proportional to the size of the torsion springs. The introduction of proportionality allowed catapult construction to be almost standardised, said Cuomo.

"Tables of specifications were compiled for quick and easy reference," she said.

Advances in catapult design led to Roman stone-throwers capable of hurling projectiles weighing 27kg a distance of 150m. Legendary engines designed by Archimedes were said to have used stones three times heavier.

The engineers saw themselves as an international community and would meet to swap ideas, said Cuomo. She said catapults marked the beginning of a quest for more powerful and accurate ways of firing projectiles against enemies and their cities, "from oversized arrows to Patriot missiles".

She added: "Ancient engineers had a role in society and often an ambivalent relationship with political power. The technology they boasted of may now be obsolete, but their anxieties, their curiosity, and their pride in their knowledge are not - perhaps the people behind the machine have not changed that much." - Sapa-dpa

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